<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="提交审核"/>
    </el-steps>

    <el-form label-width="120px">

        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 所属分类 TODO -->
        <!-- 所属分类：级联下拉列表 -->
        <!-- 一级分类 -->
        <el-form-item label="课程类别">
        <el-select
            @change="subjectLevelOneChanged"
            v-model="courseInfo.subjectParentId"
            placeholder="请选择">
            <el-option
            v-for="subject in subjectNestedList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="请选择">
        <el-option
            v-for="subject in subSubjectList"
            :key="subject.value"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        </el-form-item>


        <!-- 课程讲师 TODO -->
        <!-- 课程讲师 -->
            <el-form-item label="课程讲师">
            <el-select
                v-model="courseInfo.teacherId"
                placeholder="请选择">
                <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>
            </el-select>
            </el-form-item>

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介 TODO -->
        <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.courseDescription"/>
        </el-form-item>

        <!-- 课程封面 TODO -->
        <!-- 课程封面-->
        <el-form-item label="课程封面">

          <el-upload
            :show-file-list="false"
            :on-success="handleAvatarSuccess"
            :before-upload="beforeAvatarUpload"
            :action="BASE_API+'/admin/oss/file/upload?host=cover'"
            class="avatar-uploader">
            <img :src="courseInfo.cover">
          </el-upload>

        </el-form-item>

        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>

        <el-form-item>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="next">保存并下一步</el-button>
        </el-form-item>

    </el-form>
  </div>
</template>
<script>
import course from '@/api/course'
import teacher from '@/api/teacher'
import subject from '@/api/subject'
import Tinymce from '@/components/Tinymce'

const defaultForm = {
  title: '',
  subjectId: '',
  subjectParentId:'',//一级分类id
  teacherId: '',
  lessonNum: 0,
  courseDescription: '',
  cover: '/static/cover.jpg',
  price: 0,
  // cover: process.env.OSS_PATH + '/edu-image/cover/default-cover.jpg',
}

export default {
  components: { Tinymce },
  data() {
    return {
      courseInfo: defaultForm,
      saveBtnDisabled: false ,// 保存按钮是否禁用
      teacherList:[],
      subjectNestedList: [],//一级分类列表
      subSubjectList: [],//二级分类列表
      BASE_API: process.env.BASE_API // 接口API地址
    }
  },

  watch: {
    $route(to, from) {
      console.log('watch $route')
      this.init()
    }
  },

  created() {
    console.log('info created')
    this.init()
  },

  methods: {

    init() {
      if (this.$route.params && this.$route.params.id) {
        const id = this.$route.params.id
        console.log(id)
        this.fetchCourseInfoById(id)
      } else {
        this.courseInfo = { ...defaultForm }
        this.initTeacherList();
        this.initSubjectList();
      }

    },

    next() {
      console.log('next')
      this.saveBtnDisabled = true
      if (!this.courseInfo.id) {
        this.saveData()
      } else {
        this.updateData()
      }
    },

    // 保存
    saveData() {
      course.addCuorse(this.courseInfo).then(response => {
        this.$message({
          type: 'success',
          message: '保存成功!'
        })
        return response// 将响应结果传递给then
      }).then(response => {
          console.log(response)
        this.$router.push({ path: '/course/chapter/' + response.data })
      }).catch((response) => {
        this.$message({
          type: 'error',
          message: response.message
        })
      })
    },

    updateData() {
        this.saveBtnDisabled = true
        course.updateCourseInfoById(this.courseInfo).then(response => {
            this.$message({
                type: 'success',
                message: '修改成功!'
            })
            return response// 将响应结果传递给then
        }).then(response => {
            this.$router.push({ path: '/course/chapter/' + this.courseInfo.id })
        }).catch((response) => {
            // console.log(response)
            this.$message({
                type: 'error',
                message: '保存失败'
            })
        })
    },

    //获取讲师数据
    initTeacherList() {
        teacher.getList().then(response => {
            this.teacherList = response.data
        })
    },
    
    //获取subject树形数据
    initSubjectList() {
        subject.getNestedTreeList().then(response => {
            this.subjectNestedList = response.data
        })
    },

    //主分类改变事件
    subjectLevelOneChanged(value) {
        console.log(value)
        for (let i = 0; i < this.subjectNestedList.length; i++) {
            if (this.subjectNestedList[i].id === value) {
                this.subSubjectList = this.subjectNestedList[i].children
                this.courseInfo.subjectId = ''
            }
        }
    },

    handleAvatarSuccess(res, file) {
      console.log(res)// 上传响应
      console.log(URL.createObjectURL(file.raw))// base64编码
      this.courseInfo.cover = res.data
    },

    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2

      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },

    //根据id获取需要修改的数据
    fetchCourseInfoById(id) {
      course.getCourseInfoById(id).then(response => {
        this.courseInfo = response.data

        // 初始化分类列表
        subject.getNestedTreeList().then(responseSubject => {
          this.subjectNestedList = responseSubject.data
          for (let i = 0; i < this.subjectNestedList.length; i++) {
            if (this.subjectNestedList[i].id === this.courseInfo.subjectParentId) {
              this.subSubjectList = this.subjectNestedList[i].children
            }
          }
        })

        // 获取讲师列表
        this.initTeacherList()
      }).catch((response) => {
        this.$message({
          type: 'error',
          message: response.message
        })
      })
    },

  }
}
</script>

<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>